UMBILICAL HERNIA. 
27-3 
YI.—UMBILICAL HERNIA (OMPHALOCELE, 
EXOMPHALOS). 
By union of the visceral plates in the linea alba, the abdomen closes 
during uterine life as far as the annulus umbilicalis, which remains open 
for the umbilical cord, and after birth ceases to exist on account of 
obliteration of its vessels. In new-born animals the umbilical ring not 
infrequently appears abnormally large, so that the umbilical cord does 
not completely fill it, in consequence of which the skin and peritoneum 
either immediately or in the first few weeks after birth, yield to the 
pressure of the abdominal contents, and allow the latter to pass through 
under the skin. This condition, which occurs in different classes of 
animals, though most frequently in horses, oxen, and dogs, has been 
termed umbilical hernia, and is divided into two forms, viz., congenital, 
which is apparent at birth, and acquired, which appears during the first 
few weeks thereafter. 
As a rule, a portion of the colon or caecum, and sometimes of omentum, 
is found in the hernial sac, which is composed of skin and peritoneum, 
and which varies in size from a hazel-nut to that of a man s head. 
Pathe saw an umbilical hernia in a calf, containing a portion of the 
abomasum. 
The division usual in human surgery between umbilical hernise and herniae 
of the umbilical cord has at present no practical importance in animals. In 
the latter, the viscera lie in a dilatation of the umbilical cord, and are only 
partially, or not at all, covered by the skin, and prognosis is therefore 
usually less favourable than in the ordinary form of umbilical herniae. When 
cases occur no treatment is possible, and even in man they generally lead to 
death. 
Causes. The disease is always due to abnormal size of the umbilical 
ring. The larger this is the more easily does rupture occur. This ex¬ 
plains the hereditary character of umbilical hernise, as observed byViborg 
and Eleonet in horses, and Benkert in dogs (Stockfleth). In congenital 
umbilical herniee, the abdominal viscera have often never been in the 
abdominal cavity, because they have not been surrounded by the visceial 
plates. After birth, umbilical herniae result either from over-stretching 
of the skin covering the umbilicus, e.g., from violent tearing away of the 
umbilical cord; or they may be caused by any circumstance producing 
increase of intra-abdominal pressure, such as tympanites, excessive 
action of the abdominal constrictors during constipation (e.g., atresia ani), 
severe exertion and continuous coughing. They seldom develop in old 
animals. 
Symptoms. Umbilical hernia is recognised by the presence of a swelling 
of the size above mentioned, which lies below the umbilicus, is elastic, 
soft, sharply defined, and free from inflammatory symptoms. It usually 
